The New York Times bestseller starring Anna Pigeon from the author of Winter Study. "Action-packed…a narrative that plunges readers into mystery [and] mayhem."-The Denver PostHoping a raft trip in Big Bend National Park will lift her spirits, Anna Pigeon and her husband Paul go to southwest Texas, where the Rio Grande is running high. The beauty of the Chihuahuan Desert and the power of the river work their magic-until the raft is lost in the rapids and a young college student makes a grisly discovery. Caught in a strainer between two boulders-and more dead than alive-is a pregnant woman. Anna will soon discover that nature isn't the only one who wants to see the woman and her baby dead…